Shoe-heating device



T. LUND.

SHOE HEATING DEVICE. APPLICATION FILED FEB. 19, 1920.

Patented Sept. 20, 1921 til iiTED EN"? QFFIC THOMAS LUN'D, 0F BEVERLY, MASSAGHUSETTS, ASSIGNOR T0 UNITED SHOE IiiAGI-IINERYGGRPQRATION, OF PATERSON, NEW JERSEY, A CORPORATIOI\'2' SHOE-HEATING DEVICE.

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Specification of Letters Patent. Patented Sept, 2Q 1921 Application filed. February 19, 1920. Serial No. 359,983.

To all whom it may concern:

Be it known that I, THOMAS LUND, a citizen of the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certain Improvements in Shoe-Heating Devices, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates to the treatment of boots and shoes or shoe parts. The invention is herein set forth with especial reference to heating shoe parts or portions of boots and shoes to soften or to dry them. Such treatment is usual during the manufacture of boots and shoes of various types and may also be employed to advantage in the treatment of finished or even used shoes.

The invention will be described more particularly in connection with. the manufacture' of a McKay shoe, but as stated, is not to be regarded as limited by such disclosure. In the manufacture of the ordinary McKay shoe the insole and upper are assembled on the last and the upper is lasted and tacked or otherwise permanently fastened to the insole. The outSole' is attached by means of fastenings which extend through the outsole, upper and insole coming through therefore on the inside of the shoe, a procedure which requires that the last be removed in order that the horn of the fastening applying machine may enter the shoe and contact with the inner surface of the insole to cooperate with the external mechanism of the fastening applying machine. It is impossible to remove the last from the shoe for this operation as soon as the lasting of the upper is completed for the reason that the box toe has been rendered soft and pliable in preparation for the lasting operation and a certain amount of time is necessary for it to acquire sufficient strength and stiffness to permit the removal of the last without deforming it. This time factor 1s a serious problem in the manufacture of McKay shoes as it delays the progress of the shoes through the factory and ties up the lasts in them, therefore requiring a greater investment of capital in lasts than is desirable.

Attempts have been made to shorten this time by various drying processes. In some factories the toes of the shoes are inserted into drying chambers. As frequently carried out, this process is very wasteful of heat since the heat used is generated outside of the shoe and only a small portion of it makes its way into the shoe and becomes available, the rest escaping in all directions.

In order to secure the well-known advantages of the use of electricity, such as clean liness, convenience, economy in space, gen eration of heat at the exact point desired, and others, it has been proposed to provide a last with an electric unit embedded inits toe, supplied with current from suitable lead wires. Such apparatus is successful in securing such advantages as those set forth above. The heating unit is, however, expensive to replace in case it suffers damage through the careless handling to which all lasts are subject in shoe factories, and there is danger in entrusting very much handling of lead wires and connections to the ordinary shoe factory operator, who has no electrical training, and cannot be expected to treat such apparatus intelligently, withthe resulting possible danger to himself and the factory.

It is a principal object of my invention to provide for the use of electrical energy in heating or drying shoes'or portions of shoes and in particular box toes, economically and simply, without risk or inconvenience to the operator and without danger of rapid wear or destructionof the electrical apparatus involved. My invention contemplates broadly the application of an electrical conductor preferably of low resistance, or short circuited, in efficient.

sidered from the standpoint of apparatus,

characteristic and important features of the invention reside in novel apparatus for carr ing out this procedure. As herein exemp ified, the invention is practised by the insertion in the shoe of a short circuited electrical conductor and the placing of the shoe containing the conductor in an alternating magnetic field, as described. This conductor will act, broadly speaking, as the secondary of a transformer wound around the alternating magnetic field. The short circuited conductor may simply be a mass of metal or may have a more specialized construction, as will be pointed out below. Considered from the standpoint of apparatus, a last or shoe form equipped with such a conductor or its equivalent comprises an important feature of the invention.

Another important feature of the invention resides in the combination of a shoe (or last) support and a solenoid constructed and arranged to receive a part of the shoe (or last). A further important feature of the invention resides in the combination of a shoe support and a solenoid as already described, with a metallic element arranged to act as a transformer secondary and to be placed within the shoe. In the illustrated apparatus this element forms the toe tip of the last or form used in the shoe.

These and other features will be understood from the following description of the method as performed by the aid of a preferred form of apparatus embodying that part of the invention, and shown in the drawings, in which Figure 1 is a perspective view of my novel apparatus showing a last in position to treat the shoe being manufactured thereon, the shoe not being shown for the sake of clearness of illustration.

Fig. 2 is a cross section through the solenoid, further illustrating the structure and arrangement of the apparatus.

Figs. 3 and 4 show front views of the last illustrating a laminated and non-laminated core, respectively.

The standard 10, supported in any suitable manner, carries a number of coils or solenoids 12 arranged for use upon an alternating electrical circuit ofsuitable voltage. These coils in the embodiment shown have a sufiicient central aperture to permit the in sertion of the toe of a last which has a shoe mounted upon it. Current is supplied from the ordinary power circuit of the factory at 14 by means of a suitable rheostat 16 and switch 18. A pilot lamp 20 may be used if desired. A rest 22 holds the last and shoe in convenient position for entrance of the toe into the central aperture 24;. The last shown has a brass tip 26 containing an iron core 28, the purpose of which is to provide a path of minimum reluctance for the alternating magnetic flux generated by the solenoid 12. This core may be laminated as shown in Fig. 3, or may be solid as shown in Fig. 4. Brass is preferably used as the main body of the toe piece for the reason that it does not corrode readily under the effects of moisture and will not, therefore, damage the shoe as a totally iron toe might do. When the last shown in Fig. 4 is used, the alternating flux will pass mainly through the core 28 and will generate eddy currents therein. These eddy currents will generate a magnetic fiux of their own which opposes the impressed magnetic flux so that the secondary'current generated in the brass tip 26 Will be small. The eddy currents, however ,which are really secondary currents in the core 28, will heat the core and the heat will readily be con ducted through the brass to the shoe. In case the last shown in Fig. 3 is used, eddy currents will not flow to any great extentinf the laminated core 28 and substantially the full value of the impressed magnetic flux will be available to generate secondary currents in the tip 26. These currents flowing in a short circuited path at low resistance will, as before, generate heat which is available for heating or drying the toe of the shoe.

1 have described the invention with reference to the manufacture of the standard type of McKay shoe, having a box toe which dries or hardens under the application of heat. The invention is also useful in many other connections, for example, in the manufacture of shoes in which the self hardening or Beckwith type of box toe is used. This box toe is softened by heat and hardens on return to ordinary temperature. The invention is also useful in drying shoes which have become damp or wet in actual wear.

I have thus provided a method and appa ratus for utilizing electric energy in the heating of shoes or parts of shoes which is cheap in initial expense and in maintenance, since the solenoids 12 are practically indestructible if properly made and protected by fuses 30, and since the metallic last tip is far stronger than the main body of the last itself and will outwear any other portion of this article. My invention also makes it safe for the most ignorant or unskilled operator to handle the shoes in the manufacture of which it is being used, since the operator is not obliged to do anything more than operate the switch 18, and does not have to handle any wires or look out for any short circuits.

The advantages of electric heating, among others, cleanliness, simplicity, the generation of heat at exactly the point desired with consequent economy in energy, are thus secured by my invention, without requiring an unskilled operator to deal with electric connections, or subjecting delicate apparatus to severe usage.

In the above specification and the following claims, I have used such expressions as placing the shoe in a varying magnetic field. It is obvious that the heating action is fundamentally due to the relative moveelectrical conductor constructed and neeoeee ment of the conductor and the magnetic field,

and will be. produced by moving the con ductor in a stationary constant field, as well as by moving the field (variable or constant) with reference to the conductor, or (as shown) by merely varying the strength (algebraically considered) of the field. desire thatsuch expressions as that alluded to above be interpreted broadly as generic to the relative movement of the conductor and the magnetic field, and l have used such a aparently more restricted expressions only to secure clearness, and simplicity due to closer and more definite correspondence to the preferred embodiment shown, and to avoid cumbersome circumlocution.

Having described my invention, what 1 claim as new and desire to secure by Letters Patent of the United States is 1. A. last comprising a short circuited ranged to act as a transformer secondary,

2. A last having a metallic toe tip constructed and arranged to act as a transformer secondary.

3. A last having an iron core arranged to carry a ma netic' flux for inducing an electro-motive torce in the last.

4. A last having a metallic toe tip, and an iron core in the metallic toe tip.

5. A shoe treating apparatus comprising a support for a shoe and a solenoid constructed and arranged to envelop a part of the shoe.

6. lln a shoe heating apparatus, in combination, a support for a last and a solenoid constructed. and arranged to envelop a part of the last, and a last having a metallic part arranged to be enveloped by the solenoid.

7. lln a shoe treating apparatus, a shoe support, a solenoid arranged conveniently thereto to envelop a part of a shoe on said support, and to carry a primary current, and a metallic element arranged to act as a transformer secondary and to be placed within the shoe.

8. That improvement in methods of treating shoes or shoe parts which consists in arranging an electrical conductor in efficient heat transferring relation to the object to be treated, and placing them in a varying magnetic field, whereby the current induced in the conductor generates heat for treating the object.

9. That improvement in methods of treating shoes which consists in inserting a short circuited conductor in the shoe, and moving the shoe into a varying magnetic field, whereby the current induced in the conductor generates heat within the shoe.

10. That improvement in methods of treating shoes which consists in inserting a last having a metallic portion in the shoe, and placing the shoe in a varying magnetic field whereby the current induced in the said metallic portion generates heat within the shoe.

in testimony whereof I have signed my name to this specification.

THOMAS LUND. 

